Modern mobile communication networks face an ever increasing demand for high-bandwidth communication services under a wide variety of radio conditions. Some communication technologies have responded to this need by utilizing an expanded radiofrequency spectrum. For example, Release 8 of the 3GPP Long Term Evolution (LTE) standard utilized a 20-MHz bandwidth for carrier signals, but Release 10 is expected to utilize a spectrum of 100-MHz or more.
Because backwards compatibility is often a requirement for mobile communication networks, networks supporting use of expanded spectrums are often required to support legacy devices incapable of recognizing or utilizing their larger bandwidth. The need to support terminals having a range of different capabilities creates significant difficulties in managing resource use in such networks. To facilitate use of expanded carrier spectrums while still maintaining backwards compatibility, certain communication technologies, such as LTE, utilize a “carrier aggregation” scheme. Under such a scheme, a legacy terminal that is incapable of using the entirety of the expanded carrier spectrum will recognize the expanded spectrum as multiple separate carrier spectrums, referred to as “Component Carriers” (CCs) that are each sized to fit the capabilities of the legacy terminal. Meanwhile current-generation terminals will be able to utilize a larger carrier spectrum by aggregating multiple CCs.
However, use of multiple separate carrier spectrums can significantly complicate configuration and management of networks. For example, if the network attempts to notify a mobile device over a non-ideal radio channel that the device has been scheduled to use a particular component carrier, the mobile device may not successfully receive the notification. Even though many modern communication technologies provide procedures for a device to request retransmission of information that was not successfully received, it may be difficult or impossible for a device to determine that it has not received scheduling information if the device is uncertain what scheduling information to expect. Furthermore, while the device could simply report on all the scheduling information it receives, and thereby permit the network to determine by deduction what scheduling information the device did not receive, a significant amount of the network's transmission resource would be used up unnecessarily on such signaling when the mobile device successfully receives all the scheduling information. Thus, finding an effective scheme for communicating information about the scheduling of component carriers—one that can accommodate and adapt to transmission errors—can be critical to performance in networks that support carrier aggregation.